1. They tell you to take it slow.
"Good diets promote weight loss of no more than one to two pounds a week," says Nigel Penny, lecturer in Nutritional Science at Birmingham City University. "If you lose more than two pounds per week after the second week of dieting, it's likely that you're actually losing muscle tissue."

2. They cut out sugar, not fat.
"Many of the newer and better diets around advocate cutting down on sugar and starch rather than fat," says Marisa Peer, author of You Can Be Thin: The Ultimate Programme to End Dieting...Forever. "Your body stores excess sugar – found in starchy carbs like pasta and bread – as fat. But good fats help fill you up, and are essential for good health. A low fat diet, meanwhile, will leave you feeling tired, hungry and cranky, and won't help you maintain weight loss."

3. They tell you to always eat breakfast.
"A quality breakfast is vital for setting you up for the rest of the day," says nutritionist Jacqui Cleaver, of the New You Bootcamp. "All good diets will suggest you start your day with quality protein, sufficient good fat, and healthy carbs. Try eggs on wheat-free bread or porridge oats with berries and ground seeds."

5. They suggest permanent lifestyle changes.
"Effective weight-loss plans need to be realistic and encourage permanent lifestyle changes, rather than relying on faddy liquid formulas and powders, or upon special foods or devices," says Penny.

6. They tell you to always have protein with carbs.
"The key to long-term weight loss is keeping your blood sugar low," says Peer. "If you eat protein with your carbs, this will slow down the sugar. All good diets teach you to always add protein to carbs for this reason."

7. They are nutritionally balanced.
"In good diets, all food groups need to be represented," says Penny. "A balanced diet that includes a variety of foods is essential. Promoting the consumption of one particular 'magic' food, or advocating the avoidance of specific foods, will lead to an unbalanced diet."

8. They don't tell you to count calories.
"Counting calories is a very outdated concept and has now been proven to be an ineffective way to lose weight," says Peer. "Consuming a low fat, low calorie muffin and latte will ultimately make you pack on more pounds than having some scrambled eggs with bacon and a cup of tea."

9. They tell you to get moving too.
"Good diets will also advocate that you increase your physical activity to lose weight healthily," says Arthur.

10. They tell you to avoid processed foods.
"All good diets will tell you to avoid food made in a factory," says Peer. "That means refined, processed food. It's not even food – just a cocktail of chemicals that never goes off. You should ask yourself whether you could make the product in your own kitchen. If you couldn't make it in a regular kitchen, you shouldn't be eating it."